* [PATCH nf 1/2] netfilter: nf_tables: double hook unregistration in netns path
@ 2022-05-30 16:09 Pablo Neira Ayuso
2022-05-30 16:09 ` [PATCH nf 2/2] netfilter: nf_tables: delete flowtable hooks via transaction list Pablo Neira Ayuso
0 siblings, 1 reply; 2+ messages in thread
From: Pablo Neira Ayuso @ 2022-05-30 16:09 UTC (permalink / raw)
To: netfilter-devel
__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.
[ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27
[ 565.253682] Workqueue: netns cleanup_net
[ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[ 565.297120] Call Trace:
[ 565.300900] <TASK>
[ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[ 565.308518] raw_notifier_call_chain+0x63/0x80
[ 565.312386] unregister_netdevice_many+0x54f/0xb50
Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.
Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_tables_api.c | 54 ++++++++++++++++++++++++++---------
1 file changed, 41 insertions(+), 13 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 2c6c956c7bbc..7c9eb8e42ea6 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -222,12 +222,18 @@ static int nft_netdev_register_hooks(struct net *net,
}
static void nft_netdev_unregister_hooks(struct net *net,
- struct list_head *hook_list)
+ struct list_head *hook_list,
+ bool release_netdev)
{
- struct nft_hook *hook;
+ struct nft_hook *hook, *next;
- list_for_each_entry(hook, hook_list, list)
+ list_for_each_entry_safe(hook, next, hook_list, list) {
nf_unregister_net_hook(net, &hook->ops);
+ if (release_netdev) {
+ list_del(&hook->list);
+ kfree_rcu(hook, rcu);
+ }
+ }
}
static int nf_tables_register_hook(struct net *net,
@@ -253,9 +259,10 @@ static int nf_tables_register_hook(struct net *net,
return nf_register_net_hook(net, &basechain->ops);
}
-static void nf_tables_unregister_hook(struct net *net,
- const struct nft_table *table,
- struct nft_chain *chain)
+static void __nf_tables_unregister_hook(struct net *net,
+ const struct nft_table *table,
+ struct nft_chain *chain,
+ bool release_netdev)
{
struct nft_base_chain *basechain;
const struct nf_hook_ops *ops;
@@ -270,11 +277,19 @@ static void nf_tables_unregister_hook(struct net *net,
return basechain->type->ops_unregister(net, ops);
if (nft_base_chain_netdev(table->family, basechain->ops.hooknum))
- nft_netdev_unregister_hooks(net, &basechain->hook_list);
+ nft_netdev_unregister_hooks(net, &basechain->hook_list,
+ release_netdev);
else
nf_unregister_net_hook(net, &basechain->ops);
}
+static void nf_tables_unregister_hook(struct net *net,
+ const struct nft_table *table,
+ struct nft_chain *chain)
+{
+ return __nf_tables_unregister_hook(net, table, chain, false);
+}
+
static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *trans)
{
struct nftables_pernet *nft_net = nft_pernet(net);
@@ -7291,13 +7306,25 @@ static void nft_unregister_flowtable_hook(struct net *net,
FLOW_BLOCK_UNBIND);
}
-static void nft_unregister_flowtable_net_hooks(struct net *net,
- struct list_head *hook_list)
+static void __nft_unregister_flowtable_net_hooks(struct net *net,
+ struct list_head *hook_list,
+ bool release_netdev)
{
- struct nft_hook *hook;
+ struct nft_hook *hook, *next;
- list_for_each_entry(hook, hook_list, list)
+ list_for_each_entry_safe(hook, next, hook_list, list) {
nf_unregister_net_hook(net, &hook->ops);
+ if (release_netdev) {
+ list_del(&hook->list);
+ kfree_rcu(hook);
+ }
+ }
+}
+
+static void nft_unregister_flowtable_net_hooks(struct net *net,
+ struct list_head *hook_list)
+{
+ __nft_unregister_flowtable_net_hooks(net, hook_list, false);
}
static int nft_register_flowtable_net_hooks(struct net *net,
@@ -9741,9 +9768,10 @@ static void __nft_release_hook(struct net *net, struct nft_table *table)
struct nft_chain *chain;
list_for_each_entry(chain, &table->chains, list)
- nf_tables_unregister_hook(net, table, chain);
+ __nf_tables_unregister_hook(net, table, chain, true);
list_for_each_entry(flowtable, &table->flowtables, list)
- nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list);
+ __nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list,
+ true);
}
static void __nft_release_hooks(struct net *net)
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH nf 2/2] netfilter: nf_tables: delete flowtable hooks via transaction list
2022-05-30 16:09 [PATCH nf 1/2] netfilter: nf_tables: double hook unregistration in netns path Pablo Neira Ayuso
@ 2022-05-30 16:09 ` Pablo Neira Ayuso
0 siblings, 0 replies; 2+ messages in thread
From: Pablo Neira Ayuso @ 2022-05-30 16:09 UTC (permalink / raw)
To: netfilter-devel
Remove inactive bool field in nft_hook object that was introduced in
abadb2f865d7 ("netfilter: nf_tables: delete devices from flowtable").
Move stale flowtable hooks to transaction list instead.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
include/net/netfilter/nf_tables.h | 1 -
net/netfilter/nf_tables_api.c | 40 ++++++++-----------------------
2 files changed, 10 insertions(+), 31 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 20af9d3557b9..279ae0fff7ad 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1090,7 +1090,6 @@ struct nft_stats {
struct nft_hook {
struct list_head list;
- bool inactive;
struct nf_hook_ops ops;
struct rcu_head rcu;
};
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7c9eb8e42ea6..5c28b298c201 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1914,7 +1914,6 @@ static struct nft_hook *nft_netdev_hook_alloc(struct net *net,
goto err_hook_dev;
}
hook->ops.dev = dev;
- hook->inactive = false;
return hook;
@@ -7602,7 +7601,8 @@ static int nft_delflowtable_hook(struct nft_ctx *ctx,
{
const struct nlattr * const *nla = ctx->nla;
struct nft_flowtable_hook flowtable_hook;
- struct nft_hook *this, *hook;
+ struct nft_hook *this, *next, *hook;
+ LIST_HEAD(flowtable_del_list);
struct nft_trans *trans;
int err;
@@ -7611,13 +7611,13 @@ static int nft_delflowtable_hook(struct nft_ctx *ctx,
if (err < 0)
return err;
- list_for_each_entry(this, &flowtable_hook.list, list) {
+ list_for_each_entry_safe(this, next, &flowtable_hook.list, list) {
hook = nft_hook_list_find(&flowtable->hook_list, this);
if (!hook) {
err = -ENOENT;
goto err_flowtable_del_hook;
}
- hook->inactive = true;
+ list_move(&hook->list, &flowtable_del_list);
}
trans = nft_trans_alloc(ctx, NFT_MSG_DELFLOWTABLE,
@@ -7630,6 +7630,7 @@ static int nft_delflowtable_hook(struct nft_ctx *ctx,
nft_trans_flowtable(trans) = flowtable;
nft_trans_flowtable_update(trans) = true;
INIT_LIST_HEAD(&nft_trans_flowtable_hooks(trans));
+ list_splice(&flowtable_del_list, &nft_trans_flowtable_hooks(trans));
nft_flowtable_hook_release(&flowtable_hook);
nft_trans_commit_list_add_tail(ctx->net, trans);
@@ -7637,13 +7638,7 @@ static int nft_delflowtable_hook(struct nft_ctx *ctx,
return 0;
err_flowtable_del_hook:
- list_for_each_entry(this, &flowtable_hook.list, list) {
- hook = nft_hook_list_find(&flowtable->hook_list, this);
- if (!hook)
- break;
-
- hook->inactive = false;
- }
+ list_splice(&flowtable_del_list, &flowtable->hook_list);
nft_flowtable_hook_release(&flowtable_hook);
return err;
@@ -8327,9 +8322,8 @@ static void nft_commit_release(struct nft_trans *trans)
nft_obj_destroy(&trans->ctx, nft_trans_obj(trans));
break;
case NFT_MSG_DELFLOWTABLE:
- if (nft_trans_flowtable_update(trans))
- nft_flowtable_hooks_destroy(&nft_trans_flowtable_hooks(trans));
- else
+ nft_flowtable_hooks_destroy(&nft_trans_flowtable_hooks(trans));
+ if (!nft_trans_flowtable_update(trans))
nf_tables_flowtable_destroy(nft_trans_flowtable(trans));
break;
}
@@ -8549,17 +8543,6 @@ void nft_chain_del(struct nft_chain *chain)
list_del_rcu(&chain->list);
}
-static void nft_flowtable_hooks_del(struct nft_flowtable *flowtable,
- struct list_head *hook_list)
-{
- struct nft_hook *hook, *next;
-
- list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
- if (hook->inactive)
- list_move(&hook->list, hook_list);
- }
-}
-
static void nf_tables_module_autoload_cleanup(struct net *net)
{
struct nftables_pernet *nft_net = nft_pernet(net);
@@ -8904,8 +8887,6 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
break;
case NFT_MSG_DELFLOWTABLE:
if (nft_trans_flowtable_update(trans)) {
- nft_flowtable_hooks_del(nft_trans_flowtable(trans),
- &nft_trans_flowtable_hooks(trans));
nf_tables_flowtable_notify(&trans->ctx,
nft_trans_flowtable(trans),
&nft_trans_flowtable_hooks(trans),
@@ -8986,7 +8967,6 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
struct nftables_pernet *nft_net = nft_pernet(net);
struct nft_trans *trans, *next;
struct nft_trans_elem *te;
- struct nft_hook *hook;
if (action == NFNL_ABORT_VALIDATE &&
nf_tables_validate(net) < 0)
@@ -9117,8 +9097,8 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
break;
case NFT_MSG_DELFLOWTABLE:
if (nft_trans_flowtable_update(trans)) {
- list_for_each_entry(hook, &nft_trans_flowtable(trans)->hook_list, list)
- hook->inactive = false;
+ list_splice(&nft_trans_flowtable_hooks(trans),
+ &nft_trans_flowtable(trans)->hook_list);
} else {
trans->ctx.table->use++;
nft_clear(trans->ctx.net, nft_trans_flowtable(trans));
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
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